Vitamin B12, or cobalamin, is an essential water-soluble vitamin that plays an important role in red blood cell formation, metabolism, energy production and other body functions. Disorders such as megaloblastic anemia or pernicious anemia are caused when this vitamin is not consumed in adequate amounts through diet or when the body is unable to properly absorb and use it. A vitamin B12 deficiency might also cause nervous system effects such as loss of balance and weakness, numbness and tingling in the hands, arms, feet and legs. A vitamin B12 test accurately measures levels of this nutrient in the body. If there is a deficiency, treatment with vitamin B12 supplements or injections can help.
Step 1
Schedule an appointment with your family doctor for a blood test to check for a vitamin B12 deficiency. Discuss any symptoms with your doctor and inform him of any herbal or prescription medications and supplements you are taking, as they might affect your results. Do not eat or drink for six to eight hours before the blood test.
Step 2
Have blood collected at the doctor's office or lab. A site on the inside of the elbow or back of the hand is cleansed with an antiseptic pad. A needle is then inserted into a vein and blood is drawn into a vial. The needle is removed, and the injection site is covered with a sterile bandage.
Step 3
See your family doctor to discuss your vitamin B12 test results. A measurement of less than 200 pg/mL of vitamin B12 indicates a deficiency of this nutrient. Elderly adults might have symptoms, even with vitamin B12 levels between 200 and 500 pg/mL. Your doctor will also diagnose the cause of your deficiency and provide options for treatment.
Tips and Warnings
- Vitamin B12 deficiency might have an underlying cause, such as Crohn's disease or other gastrointestinal disorders and previous surgeries. Inform your doctor of your past medical history and any symptoms you are experiencing.
- Having blood drawn for the vitamin B12 test can cause some side effects, such as fainting or feeling light-headed, excessive bleeding or a hematoma, in which blood accumulates under the skin. An infection at the site is also possible.
Things You'll Need
- Doctor's appointment
- Blood test
- Test results
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